1. Field of the Invention
The present invention relates to a photometric device having split photometric sensors.
The present application is based on Japanese Application Nos. Hei. 9-333270 and 10-279991, which are incorporated herein by reference.
2. Description of the Related Art
It is known to provide a camera with a photometric device. A light receiving surface of the photometric sensor is disposed on or near an expected focal plane of a subject image, so that the sensor measures the brightness of the subject image formed on the light receiving surface. Further, some photometric devices have split photometric sensors in which the light receiving surface is divided into a plurality of regions. The brightness of the subject image incident upon each split photometric region can be measured.
The light receiving surface of the split photometric sensor is divided into the split photometric regions of the desired shapes, and the split photometric regions are separated from each other by an insensitive region so as to prevent crosstalk or locate the wirings. FIG. 7 shows an example of a split photometric sensor 71. This split photometric sensor 71 has six-split sensor regions 73A to 73F. These sensor regions 73A to 73F are separated by an insensitive region 75.
Accordingly, it is not possible to measure the luminance and thus brightness of the subject image formed on the insensitive region 75. FIG. 7 three-dimensionally illustrates the sensitivity distribution of this split photometric sensor 71. In a three-dimensional sensitivity distribution 70, the higher the ridge, the higher the sensitivity. As is apparent from the photometric sensitivity distribution 70, the insensitive region 75 portion becomes a trough, and the distribution is discontinuous from the center toward the periphery. In the drawing, reference numeral 41 denotes a photographing image plane.
If the width of the insensitive region 75 is made narrow, the crosstalk increases, to lower the accuracy of split photometry. In other words, the more compact the split photometric sensor 71 is made, and the more the number of split photometric regions is increased, the greater the proportion of the insensitive region 75 to the photometric region becomes, and thus the larger the unevenness in photometric sensitivity becomes.